Radiography; Terms Flashcards
Angiocardiography
Radiography of heart chambers & major vessels, water soluble iodine contrast - opacify
Anode
Tube head target
Arthrography
Contrast radiography of joint space - demo capsule distension/rupture/cartilage problems
Atom
Smallest possible particle of an element that retains all properties of the element.
Protons, neutrons, electrons
Atomic number
Number of protons possessed by an element
Bronchography
Contrast radiography of bronchial tree.
Diagnose; foreign bodies, tumours, lung lobe torsion
Cathode
Tube head filament. Negatively charged electrode where electron stream generated by thermionic emission
Clearing time
Time taken for removal of unexposed halide during fixing
Collimation
Limits of area of interest to be radiographed
Compression band
Tight support- reduce large areas; chest & abdomen
Contrast
Diff between shades on radiograph
Contrast media
Agent to opacify structure/organ - better visualisation
Contrast radiography
Radio graphic studies utilising contrast media - improved assessment of shape/size/structure
Controlled area
Area in room specific for radiography
Crossed grid
Stationary grid- lead strips, alternating with strips radiolucent material. Vertically & horizontally.
Efficient, expensive
Definition
Sharpness/clarity of structures of interest
Density
Degree of blackness
Developer
Alkaline solution (phenidone-hydroquinone); 1st stage processing radiograph
Dichroic fog
Yellow staining - insufficient rinsing/exhausted fixer
Double contrast radiography
Radiography of hollow organ using positive(water soluble iodine) & negative contrast agents(room air/O2)
Effective focal spot
Small area where x-ray beam appears to originate
Electron
Negatively charged particle revolving around nucleus of atom
Element
Simple chemical substance cannot be broken down by chemical means
Filament
Tungsten coil of tube head cathode (negatively charged electrode)
Film focal distance
Distance between focal spot & radiographic film
75-100cm
Film-screen combination
Selection of compatible film type & intensifying screen of certain speed & definition
Fixer
Acidic solution (thiosulphate) - removes unexposed silver halide crystals = permanent image
Flat film
Low contrast radiograph - grey - underdeveloped
Focal spot size
Size of area from primary beam emerges.
Focused grid
Stationary grid; vertical strips alternating lead and radiolucent material. Slopes on sides
Fogging
Undesirable darkening of radiograph
Gastrogram
Contrast radiograph of stomach
Grid
Prevent scatter. Placed between patient & cassette
Grid factor
Amount mAs must be ++ to compensate for absorption of primary beam when using grid
Grid ratio
Height of lead strips to width of radiolucent interspaces
Intensifying screen
In cassette, phosphorescent crystals - intensify effect of x-ray on radiographic film
Ionising radiation
Emanation of energy in form of electromagnetic x-ray waves
Kilovoltage (kV)
Potential diff between filament & target of X-ray tube head; penetrating power of primary beam
Light beam diaphragm
Controls size of x-ray beam
Line voltage compensator
Controls fluctuations in mains electricity
Milliamperage mA
Quantity of x-Ray’s in emergent beam
Milliampere seconds mAs
Combo of x-ray quantity & exposure time
Monochromatic film
Film sensitive only to blue light emitting screens
Movement blur
Undesirable effect on exposed films - instability of equipment
Myelography
Radiographic exam of spinal cord - radio opaque contrast medium - cisternall/lumbar puncture into sub-arachoid space
Negative contrast agent
Radio-opaque medium; better visualisation
Neutron
Uncharged particles in nucleus of atom
Non-screen film
Film - not used with intensifying screens.
Intra-oral radiograph
Object film distance
Distance between area to be radiographed & the film.
Should be close as possible
Orthochromatic film
Film sensitive to both blue & green light emitting screens
Parallel grid
Stationary grid - alternating vertical strips of lead & radiolucent material
Penumbra effect
Undesirable effect; blurring of image due to large focal spot size
Photon
Energy packet released when rapidly moving electrons are slowed down/halted
Pneumocystogram
Contrast radiograph of bladder utilising gas as negative contrast agent - enable better visualisation
Portal venography
Contrast radiography of vasculature of liver. Contrast agent intro via hepatic portal vein
Positive contrast agent
Element - outline endothelial/mucosal surfaces = better visualisation.
Whiter due to high atomic no.
Potter Bucky diaphragm
Moving grid, in radiograph table tops.
No grid lines, expensive.
Primary beam
Useful beam of polychromatic x-Ray photons - create image on radiographic film
Proton
Positively charged particle in nucleus of atom
Pseudo-focused grid
Stationary grid; vertical slats, shorter @ edge
RPA (Radiation Protection Adviser)
Experienced external adviser; draws up local rules & written systems of work
RPS (Radiation Protection Supervisor)
Senior vet; ensures all radiographs safe and in accordance with local rules and systems
Radiography
Production of diagnostic film records of internal body structures, by exposure of film sensitive to x-Ray’s
Radiology
Science of radiation @ its use in diagnosis & treatment of disease
Reduction
Chemical process; image produced during development.
Silver bromide ions - crystals of metallic silver, bromide ions lost in solution
Actual focal spot
Area of tungsten target, stream of electrons produced at cathode impinge at high speed
Retrograde urethrogram
Contrast radiography; male urethra, water soluble iodine + contrast medium- improved visualisation.
Haematuria, dysuria, urinary incontinence
Retrograde vaginourethrogram
Contrast radiograph; female urethra, water soluble iodine + contrast medium.
Intro via Foley catheter
Scattered radiation
Secondary radiation; produced by lower energy x-ray photons, emerge from patient
Soot & Whitewash
Exposed film; v high contrast & few shades grey.
Cause low kilovoltage
Stop bath
Intermediate wash bath in manual development; water, may be weak acid - halt development
Tanning
Hardening of developed radiograph during fixing
Target
Positively charged electrode of X-ray tube upon which electrons generated at the filament impinge
Thermionic emission
Electron cloud released; following heating of filament, passing electrical current through it
X-ray tube head
X-Ray’s generated here.
Contains filament & target